Touch panel, liquid crystal panel, liquid crystal display device, and touch panel-integrated liquid crystal display device

Abstract

A touch panel includes: an infrared light transmitting material through which infrared light is transmitted and which has a surface as a touch surface ( 20 ) touched by a detection subject; area sensors ( 3 ) including photo sensor elements ( 4 ) below a touch region, which is touched by the detection subject, of the infrared light transmitting material; and infrared light sources ( 1 ) provided outside the touch region, the infrared light sources ( 1 ) emitting infrared light along said surface of the infrared light transmitting material such that an entire circumference of the detection subject touching the touch surface ( 20 ) is irradiated with the infrared light, the touch panel detecting a position touched by the detection subject so that the photo sensor element ( 4 ) receives, among infrared light emitted by the infrared light sources ( 1 ) along said surface, infrared light reflected by the detection subject and transmitted through the infrared light transmitting material.

The invention claimed is: 
     
       1. A touch panel comprising:
 an infrared light transmitting material through which infrared light is transmitted and which has a surface being used as a touch surface, the touch surface being touched by a detection subject; 
 infrared light sensors including a plurality of infrared light receiving elements provided below a touch region of the infrared light transmitting material, the touch region being touched by the detection subject; and 
 a plurality of infrared light sources provided in an outside of the touch region of the infrared light transmitting material, the plurality of infrared light sources being configured to emit infrared light along said surface of the infrared light transmitting material such that an entire circumference of the detection subject touching the touch surface is irradiated with the infrared light, 
 the touch panel detecting a position touched by the detection subject in such a manner that at least one of the infrared light sensors receives, among infrared light emitted by the infrared light sources along said surface of the infrared light transmitting material, infrared light which is reflected by the detection subject and is transmitted through the infrared light transmitting material, 
 wherein: 
 a light path changing section is provided in the outside of the touch region, the light path changing section changing a light path of infrared light emitted by the infrared light sources so that the light path becomes in parallel with said surface of the infrared light transmitting material, 
 wherein: 
 the infrared light transmitting material includes an extension section which is extended from the infrared light transmitting material and is provided in the outside of the touch region; 
 the extension section has a surface which is on the side of the touch surface, the surface being provided with the light path changing section having an inclined surface which is inclined with respect to the touch surface; 
 the infrared light is emitted to the inclined surface; and 
 the following formula (1) is satisfied:
   θ=arcsin [ n ·sin {arcsin( k )−θ 0 }]  (1),
 
 
 where n denotes a relative refractive index of the infrared light transmitting material with respect to an absolute refractive index of air, θ 0  denotes an angle by which the inclined surface is inclined with respect to the touch surface, θ denotes an angle of incidence of infrared light with respect to the inclined surface, and k is 0.975 or greater and not greater than 1. 
 
     
     
       2. The touch panel as set forth in  claim 1 , wherein:
 each of the infrared light sensors further includes an optical filter for shielding a respective one of the infrared light receiving elements from visible light. 
 
     
     
       3. The touch panel as set forth in  claim 1 , wherein:
 a reflection member is provided so as to surround each of the infrared light sources, the reflection member reflecting infrared light emitted by the infrared light source so as to guide the infrared light to said surface of the infrared light transmitting material, the reflection member being provided so as to be adjacent to a surface of a part of the infrared light transmitting material which part is extended to and provided in the outside of the touch region; and 
 the infrared light transmitting material and the reflection member serve as the light path changing section. 
 
     
     
       4. The touch panel as set forth in  claim 1 , wherein:
 the infrared light sources are provided below the touch surface of the infrared light transmitting material. 
 
     
     
       5. The touch panel as set forth in  claim 1 , wherein:
 the infrared light sources are positioned so as to face corner sections of the touch region. 
 
     
     
       6. A liquid crystal display device comprising a liquid crystal panel which comprises a touch panel as set forth in  claim 1 . 
     
     
       7. A touch panel-integrated liquid crystal display device, comprising:
 a touch panel as set forth in  claim 1 , 
 the infrared light transmitting material being one of a pair of substrates included in a liquid crystal panel, the liquid crystal panel including a liquid crystal layer sandwiched by the substrates. 
 
     
     
       8. A touch panel comprising:
 an infrared light transmitting material through which infrared light is transmitted and which has a surface being used as a touch surface, the touch surface being touched by a detection subject; 
 infrared light sensors including a plurality of infrared light receiving elements provided below a touch region of the infrared light transmitting material, the touch region being touched by the detection subject; and 
 a plurality of infrared light sources provided in an outside of the touch region of the infrared light transmitting material, the plurality of infrared light sources being configured to emit infrared light along said surface of the infrared light transmitting material such that an entire circumference of the detection subject touching the touch surface is irradiated with the infrared light, 
 the touch panel detecting a position touched by the detection subject in such a manner that at least one of the infrared light sensors receives, among infrared light emitted by the infrared light sources along said surface of the infrared light transmitting material, infrared light which is reflected by the detection subject and is transmitted through the infrared light transmitting material, 
 wherein: 
 a light path changing section is provided in the outside of the touch region, the light path changing section changing a light path of infrared light emitted by the infrared light sources so that the light path becomes in parallel with said surface of the infrared light transmitting material, 
 wherein: 
 the infrared light transmitting material includes an extension section which is extended from the infrared light transmitting material and is provided in the outside of the touch region; 
 the extension section has a surface which is on the side of the touch surface, the surface being provided with the light path changing section having an inclined surface which is inclined with respect to the touch surface; 
 the infrared light is emitted to the inclined surface, and the inclined surface is provided with (i) first regions through which infrared light is transmitted and (ii) second regions through which infrared light is not transmitted, the first regions and the second regions being arranged alternately; and 
 the following formula (2) is satisfied:
   θ=arcsin((sin(arcsin( k )−θ 0 )− m·λ   2   /P )/ n )  (2),
 
 
 where n denotes a relative refractive index of the infrared light transmitting material with respect to an absolute refractive index of air, θ 0  denotes an angle by which the inclined surface is inclined with respect to the touch surface, λ 2  denotes a wavelength of infrared light emitted along the surface of the infrared light transmitting material, θ denotes an angle of incidence of infrared light with respect to the inclined surface, P denotes a distance between centers of adjacent ones of the first regions, k is 0.975 or greater and not greater than 1, and m is an integer of 0 or greater. 
 
     
     
       9. The touch panel as set forth in  claim 8 , wherein:
 each of the infrared light sensors further includes an optical filter for shielding a respective one of the infrared light receiving elements from visible light. 
 
     
     
       10. The touch panel as set forth in  claim 8 , wherein:
 a reflection member is provided so as to surround each of the infrared light sources, the reflection member reflecting infrared light emitted by the infrared light source so as to guide the infrared light to said surface of the infrared light transmitting material, the reflection member being provided so as to be adjacent to a surface of a part of the infrared light transmitting material which part is extended to and provided in the outside of the touch region; and 
 the infrared light transmitting material and the reflection member serve as the light path changing section. 
 
     
     
       11. The touch panel as set forth in  claim 8 , wherein:
 the infrared light sources are provided below the touch surface of the infrared light transmitting material. 
 
     
     
       12. The touch panel as set forth in  claim 8 , wherein:
 the infrared light sources are positioned so as to face corner sections of the touch region. 
 
     
     
       13. A liquid crystal display device comprising a liquid, crystal panel which comprises a touch panel as set forth in  claim 8 . 
     
     
       14. A touch panel-integrated liquid crystal display device, comprising:
 a touch panel as set forth in  claim 8 , 
 the infrared light transmitting material being one of a pair of substrates included in a liquid crystal panel, the liquid crystal panel including a liquid crystal layer sandwiched by the substrates. 
 
     
     
       15. A touch panel comprising:
 an infrared light transmitting material through which infrared light is transmitted and which has a surface being used as a touch surface, the touch surface being touched by a detection subject; 
 infrared light sensors including, a plurality of infrared light receiving elements provided below a touch region of the infrared light transmitting material, the touch region being touched by the detection subject; and 
 a plurality of infrared light sources provided in an outside of the touch region of the infrared light transmitting material, the plurality of infrared light sources being configured to emit infrared light along said surface of the infrared light transmitting material such that an entire circumference of the detection subject touching the touch surface is irradiated with the infrared light, 
 the touch panel detecting a position touched by the detection subject in such a manner that at least one of the infrared light sensors receives, among infrared light emitted by the infrared light sources along said surface of the infrared light transmitting material, infrared light which is reflected by the detection subject and is transmitted through the infrared light transmitting material, 
 wherein: 
 a light path changing section is provided in the outside of the touch region, the light path changing section changing a light path of infrared light emitted by the infrared light sources so that the light path becomes in parallel with said surface of the infrared light transmitting material, 
 wherein: 
 a light guide member through which infrared light is transmitted is provided in the outside of the touch region of the infrared light transmitting material; and 
 the light guide member has a reflection surface serving as the light path changing section. 
 
     
     
       16. The touch panel as set forth in  claim 15 , wherein:
 each of the infrared light sensors further includes an optical filter for shielding a respective one of the infrared light receiving elements from visible light. 
 
     
     
       17. The touch panel as set forth in  claim 15 , wherein:
 the infrared light sources are positioned so as to face corner sections of the touch region. 
 
     
     
       18. A liquid crystal display device comprising a liquid crystal panel which comprises a touch panel as set forth in  claim 15 . 
     
     
       19. A touch panel-integrated liquid crystal display device, comprising:
 a touch panel as set forth in  claim 15 , 
 the infrared light transmitting material being one of a pair of substrates included in a liquid crystal panel, the liquid crystal panel including a liquid crystal layer sandwiched by the substrates.